Three weeks ago, Orlando Cruz signed up for a Twitter account and sent out his first message: 25 words, first in Spanish and then English, that changed his sport forever.

"As a boxer, I am proud to tell the world that I have always been and always will be a proud Puerto Rican gay man," the fighter, nicknamed "El Fenomeno," tweeted October 3.

With that tweet, Cruz became the first openly homosexual fighter in pro boxing. His reasons for coming out were unambiguous. "The gay community should have the same rights as the heterosexual community," Cruz, whose family lives in Miami, told the Los Angeles Times. "I want to be part of that movement to make that happen here."

Though homophobia is far from extinct, the tide of public opinion seems to pull inexorably against bigotry. Last year, Congress repealed Don't Ask, Don't Tell, allowing gays and lesbians to serve openly in the military. Following a string of highly publicized suicides, schools across the country began taking an aggressive stance against bullying.

Yet in 2012, none of the four major American sports has ever seen an active, openly gay player like Cruz. Pro sports are truly America's last closet.

The ever-shifting struggle over gay rights in sports has often centered on South Florida athletes, from diver Greg Louganis's landmark decision to come out two decades ago to Miami Heat legend Tim Hardaway's cowardly homophobia to Cruz's brave move.

More recently, pro athletes have done more than try to eradicate bigotry in their games; they've become the public faces for their communities' LGBT struggles, from a punter on the Minnesota Vikings to the captain of the Florida Panthers.

"We're all equal, and we need to give everyone an equal chance," says Brian Campbell, who won the Lady Byng Memorial Trophy for sportsmanship while leading the Panthers to the playoffs last year. "As an athlete, you should want to play against the best regardless of their color or sexual orientation or anything else."

It wasn't until the 1970s that retired pro athletes began coming out; in 1975, three years after leaving the Green Bay Packers, David Kopay became the first openly gay ex-NFL player; tennis legend Billie Jean King was outed via a lawsuit in 1981, and the next year, former Oakland A's outfielder Glenn Burke became the first Major League Baseball player to announce he was gay.

Louganis, the former University of Miami star who became an international superstar by taking four gold medals in consecutive Olympics, may have made his biggest splash in 1994, when he announced not only that he is gay but HIV-positive.

"Greg coming out made a huge difference to the gay community," says Fawn Yacker, project director of the Last Closet, a San Francisco-based nonprofit that aims to make pro sports more welcoming to gay athletes. "He was such a household name that it may have been a shock at first, but the reaction was, 'Wow, I liked that guy, and he's gay.' It started a conversation."

Even with retired players increasingly taking the leap, intolerance has stubbornly hung on in pro sports.

Take the case of Esera Tuaolo, who spent nine years with five NFL teams. He regularly witnessed fistfights in the locker room over players calling each other gay, and coaches sometimes joined in the hazing. It was enough to make him contemplate suicide. Tuaolo came out in 2002 after hanging up his cleats.

"It was part of my life," he says today. "That was my career. Everyone makes sacrifices in their life. For me, I had to sacrifice part of my humanity."

A few years after Tuoalo's retirement, Hardaway, the Heat legend, went on a homophobic rant on live radio just after former Orlando Magic center John Amaechi became the first former NBA player to come out.

"You know, I hate gay people, so I let it be known," Hardaway said. "I don't like gay people, and I don't like to be around gay people. I am homophobic. I don't like it. It shouldn't be in the world or in the United States." (He later apologized.)

For fans, hearing the controversial debate played out so publicly in a single week was unprecedented, says Cyd Ziegler, cofounder of Outsports.com, a gay-friendly sports website. "Professional sports took a jump in our culture then," Ziegler says. "They saw both sides in that one week... I think ever since that moment, the progress of gay equality in sports has sped up a lot."

Today it's generally agreed that sports culture is more accepting of homosexuality, and the evidence is in the headlines. Last year, Phoenix Suns President Rick Welts came out, and former University of Miami football star Michael Irvin appeared on the cover of Out magazine, opening up in an interview about his gay brother. Former Pittsburgh Pirates owner Kevin McClatchy also came out as gay this year, as did retired Seattle ­Seahawk Wade Davis — the fourth NFL player to come out after retirement. And teams across the professional sports gamut are releasing It Gets Better videos with anti-gay-bullying messages, inspired by alt-weekly sex columnist Dan Savage.

"I think the last year has seen a tipping point for a variety of reasons," says Dan Woog, author of Jocks: True Stories of America's Gay Male Athletes. "Everybody was sort of waiting for an athlete to come out in one of the major sports, and what happened instead was a lot of activity on the straight-ally front."

Lately, pro athletes have also been ever more willing to use their celebrity for LGBT campaigns, both in their leagues and in their communities.

In Minnesota, where a near-deadlocked vote to constitutionally define marriage as between a man and a woman looms on next month's ballot, Vikings punter Chris Kluwe has emerged as the unlikely spokesman for Vote No. Kluwe garnered millions of hits in September with an op-ed for Deadspin slamming a Maryland congressman for questioning NFL players' right to stick up for gay people.

"He's going to save it for us, I swear it to you," Tracy Call, founder of Minnesotans for Equality, says of Kluwe's work against the amendment.

In South Florida, the Panthers' Campbell has taken perhaps the most visible stand by signing on to You Can Play, an NHL-wide effort to take homophobia out of the locker room. The campaign was started in March by Brian Burke, president of the Toronto Maple Leafs, after his openly gay son died in a car crash.

"The attitudes are finally changing, and it's just because it's talked about more. Everyone is much more educated now," Campbell says. "If someone did come out in the NHL now, I believe guys would be totally fine with it. If he's good enough to play, let's have him."

Pro sports certainly haven't eradicated homophobia. In September, Toronto Blue Jays shortstop Yunel Escobar was suspended for etching "You are a faggot" in Spanish on his eye black. Athletes are routinely bombarded with gay slurs on Twitter after a bad play.

And even with the emergence of straight allies like Kluwe and Campbell, the final test has yet to come for the four major leagues. Real change occurs when a gay athlete like Orlando Cruz takes the ultimate step: coming out while still competing.

When they do, they'll confront a scene like Cruz did last Friday, when he stepped into the ring in Kissimmee Civic Center to fight Jorge Pasos in his first bout since his bombshell Twitter messages. Everyone from the BBC to NPR to HBO's Real Sports was there to document the moment and to show millions of viewers that a gay athlete can compete.

"There's only one thing that will knock down that wall entirely," says Dave Pallone, a gay former baseball umpire and author of Behind the Mask: My Double Life in Baseball. "That will be for a male athlete in one of the major sports to come out while he's still playing."